A couple of levels before Tammany Dr Langford died during a battle and I finished it before he revived. Now he's staying dead.
Even outside of battle he just stays in place, dead. I can't revive him as no-one else has a medical skill
It was fine until I got to Tammany as you need everyone to be in the same place to escape, so I can't progress
Please help, as I don't want to restart!

We played around a bit trying to reproduce your error. Every time a combat ends, the characters revive. But... We could reproduce the error under a very specific set of circumstances (which, if this happened to you, makes you very unlucky):

1) A party member is knocked out and falls to the ground
2) Another party member stands on the same spot as the knocked out party member
3) The combat ends and another combat immediately starts (which I think only happens once in New Barbary).

What normally happens is:

a) party members automatically revive after combat ends
b) if a party member is standing on the same tile as an unconscious party member, he will move to a new location and the unconscious party member will then revive.

So, if a new combat starts before the party member can move aside to let the revived party member up, then he stays dead.

So this goes in the pot for the next patch. But it won't help you as you have done at least one big level after that (Mano Nera). But if you tell us which archetype and difficulty level then we can try to get a saved game to you to continue.